Covalently Linking Reduced Graphene Oxide Facilitated Electrodeposition of MoS₂ on Silicon Pyramidal Photocathode To...

In recent years, increasing attention has been paid to photoelectrochemical (PEC) hydrogen production owing to the utilization of sustainable solar energy and its promising performance. Silicon-based composites are generally considered ideal materials for PEC hydrogen production. However, slow reaction kinetics and poor stability are still key factors hindering the development of silicon-based photoelectrocatalysts. Herein, we present an n⁺-p Si pyramidal photocathode assembly method to load reduced graphene oxide (rGO) onto the surface of the n⁺-p Si pyramid by covalently linking (Si/rGO). rGO is utilized as a conductive layer to reduce the interfacial charge-transfer resistance. Then, MoS₂ can be successfully electrodeposited on the surface of Si/rGO to form the Si/rGO/MoS₂ composite, which possesses excellent PEC hydrogen evolution performance with a high and stable photocurrent of -41.6 mA cm^-2 and a hydrogen evolution rate of about 18.1 μmol min^-1 cm^-2 under 0 V (vs RHE). The covalently linking rGO layer effectively enhances the transfer of photogenerated carriers between the Si substrate and MoS₂. MoS₂ provides abundant hydrogen evolution active sites, which accelerate the surface reaction kinetics, as well as a protective layer for the Si pyramidal array structure. This work provides a low-cost, convenient, and efficient way of preparing silicon-based photocathodes.